CLOCK-controlled polyphonic regulation of circadian rhythms through canonical and noncanonical E-boxes

H Yoshitane, H Ozaki, H Terajima, NH Du… - … and cellular biology, 2014 - Am Soc Microbiol
H Yoshitane, H Ozaki, H Terajima, NH Du, Y Suzuki, T Fujimori, N Kosaka, S Shimba…
Molecular and cellular biology, 2014Am Soc Microbiol
In mammalian circadian clockwork, the CLOCK-BMAL1 complex binds to DNA enhancers of
target genes and drives circadian oscillation of transcription. Here we identified 7,978
CLOCK-binding sites in mouse liver by chromatin immunoprecipitation-sequencing (ChIP-
Seq), and a newly developed bioinformatics method, motif centrality analysis of ChIP-Seq
(MOCCS), revealed a genome-wide distribution of previously unappreciated noncanonical E-
boxes targeted by CLOCK. In vitro promoter assays showed that CACGNG, CACGTT, and …
Abstract
In mammalian circadian clockwork, the CLOCK-BMAL1 complex binds to DNA enhancers of target genes and drives circadian oscillation of transcription. Here we identified 7,978 CLOCK-binding sites in mouse liver by chromatin immunoprecipitation-sequencing (ChIP-Seq), and a newly developed bioinformatics method, motif centrality analysis of ChIP-Seq (MOCCS), revealed a genome-wide distribution of previously unappreciated noncanonical E-boxes targeted by CLOCK. In vitro promoter assays showed that CACGNG, CACGTT, and CATG (T/C) G are functional CLOCK-binding motifs. Furthermore, we extensively revealed rhythmically expressed genes by poly (A)-tailed RNA-Seq and identified 1,629 CLOCK target genes within 11,926 genes expressed in the liver. Our analysis also revealed rhythmically expressed genes that have no apparent CLOCK-binding site, indicating the importance of indirect transcriptional and posttranscriptional regulations. Indirect transcriptional regulation is represented by rhythmic expression of CLOCK-regulated transcription factors, such as Krüppel-like factors (KLFs). Indirect posttranscriptional regulation involves rhythmic microRNAs that were identified by small-RNA-Seq. Collectively, CLOCK-dependent direct transactivation through multiple E-boxes and indirect regulations polyphonically orchestrate dynamic circadian outputs.
American Society for Microbiology